In existing aircraft, the engines, such as the jet engines, are suspended below the wing by complex attachment devices, also referred to as EMS (Engine Mounting Structures), or attachment pylons. The attachment devices commonly employed have a rigid structure, referred to as the primary structure. This primary structure forms a box section, that is to say it is formed by the assembly of lower and upper spars that are connected together by a plurality of transverse stiffening ribs that are located inside the box section. The spars are arranged in the upper and lower faces, while lateral panels close the lateral faces of the box section.
In a known manner, the primary structure of these pylons is designed to allow the static and dynamic forces brought about by the engines, such as the weight, the thrust, or the various dynamic forces, to be transmitted to the wing.
In solutions known from the prior art, forces are conventionally transmitted between the engine and the primary structure by an attachment consisting of a front engine attachment, a rear engine attachment and a device for taking up thrust forces. A conventional exemplary embodiment of the rear engine attachment is shown in FIG. 1.
This rear engine attachment connects the exhaust casing of the engine to the primary structure of the attachment pylon in the form of a box section. To this end, the attachment comprises a body and a plurality of shackles that are articulated on the engine attachment body and on the exhaust casing. More specifically, the body comprises two stages of beams that are stacked in the vertical direction. These are one or more upper beams that are fixed by bolts to the outer face of the lower spar that closes the box section, and one or more lower beams that are fixed by bolts to the upper beams. It is this lower beam which carries, in an articulated manner, the shackles. More commonly, the upper beams are referred to as “intermediate fittings” while a single lower beam, more commonly referred to as “engine beam”, is generally employed. It should be noted that during the removal of the engine, for example in order to carry out maintenance operations, disconnection takes place at the interface referenced, which is located between the upper beams that remain fixed to the box section and the lower beam that remains fixed to the engine via the shackles.
Although this solution proves to be satisfactory in many respects, it can be improved. In particular there is a need to reduce its overall mass.